A planoconvex lens is made of a material of refractive index μ = 1.5. The radius of curvature of curved surface of the lens is 20 cm. If its plane surface is silvered, the focal length of the silvered lens will be :

Electromagnetic radiation of frequency v frequency, velocity v and wavelength λ, in air enters a glass slab of refracive index μ. The frequency, wavelength and velocity of light in the glass slab will be, respectively

If f_v and f_n are the focal lengths of a convex lens for violet ad red light respectively and F_V and F_R are the focal lengths of concave lens for violet and red light respectively, then we have

Diameter of human eye lens is 2mm. What will be the minimum distance between two points to resolve them, which are situated at a distance of 50m from eye? [The wavelength of light is 5000 Å]

For the given incident ray as shown in figure, the condition of total internal reflection of the ray will be satisfied if the refractive index of block will be

A transparent cube contains a small air bubble. Its apparent distance is 2 cm when seen through one face and 5 cm when seen through other face. If the refractive index of the material of the cube is 1.5, the real length of the edge of cube must be :

Focal length of a convex lens of refractive index 1.5 is 2 cm. Focal length of lens when immersed in a liquid of refractive index of 1.25 will be

A convex lens and a concave lens, each having same focal length of 25 cm, are put in contact to form a combination of lenses. The power in diopters of the combination is :

The focal lengths of a converging lens measured for violet, green and red colours are f_V,f_G,f_R respectively. We will find

Rainbows are formed by